Feedback on the first production run of LA46 sets has been really good.

I have sufficient requests to proceed with a second production run as of 25th July.

The sets will again include piston/liner/rod/pin/head/shim. The head is mandatory as I've increased the liner thickness at the top for extra strength during production and service. The revised port timing (as opposed to stock) and angling is giving great results.

I bet the guys into Fox 35 speed would be interested if you offered them an ABC setup like the ones FOX used to offer. Maybe your ABC setp for the 36X P/L can be modified to fit the Stunt case?Too bad no one near to me ( AlbanyNY) playing with Fox speed.Lyle

A number of people have sent pm's expressing concerns that changing the port timing to proven stunt numbers will bring a loss of power. (The stock timing is 142 exhaust and 116 transfers.)

This may be true in the case of outright peak 2 cycle power.

But with proven stunt timing figures the engine will deliver good - controllable stunt runs. If more power is sought a larger venturi or more nitro will give that whilst maintaining the quality of run characteristics.

I've just received a temporary sample engine to look at and make final decisions. So far enough people have committed to an order for me to be able to do an initial production run if I decide to proceed.

BrianI've marvelled at the LA46 for years. The LA46 numbers are terrible ... it shouldn't work as a good stunt motor....... but for some reason they work really well. The run is not a fullout two cycle..... its a really good stunt run as is,for almost everyone. I don't know why, I wouldn't have thought so but they work with the high timing and big blowdown. Go figure. I don't know if anyone has ever tried one with normal timing. Somehow I think an LA46 with normal timing wouldn't be an LA46.Frank

I have modified 2 LA 46s by simply but CAREFULLY filing the transfer ports with a flat needle file, measuring the height first with calipers and then removing 25 thousandths leaving the roof angle at 90 degrees and the same height all the way across. This is exactly what Derek Pickard was doing and I found this mod in an article he produced back in the..well back a while ago. There is minimal power loss but that was not an issue FOR ME. The motor now runs in a solid 4 and just breaks at the tops lightly (depending on prop, compr, venturi size etc) but the real deal here is...it does this EVERY time. Derek even states in his article that "right every time counts a lot". I am NOT saying the stock motor doesn't run right every time for everybody...it just didn't FOR ME. As far as stunt timing for Brian's P/L sets as long as we don't expect a wet 2 run and more of a 4/2 run I know I would be VERY pleased as my hack at the motor produced exactly the results I wanted. His "mods" no doubt would be an even greater improvement. I can only attest to modified timing. Mike Scott, Doug Moon and Chris Rigotti can attest to the motor runs i am getting on this motor....consistent is the best word I think. Again, not that others have not gotten consistent runs on a stock motor, I just didn't. NOW...FUEL CONSUMPTION!!! That's the real caveat...stock I could do the pattern on 3.25 to 3.5 ozs of 5/22 Powermaster...that is amazing to me...a pattern with 10 laps to spare on a .46 motor on 3.5 ozs pulling a 48 oz Cardinal!!! Incredible. Modified motor uses 5 ozs....every bit of it, same fuel (with 1 head shim). Just my 2 cents...if Brian makes these i will buy several for all, well not all, I would leave some stock, my 6 LA46s.

I'm going to look at angling the ports a little towards non exh side of the cylinder. It won't be much help on fuel economy because the liner is so thin and any angle on the port sides won't have much effect. But every little bit counts in trying to stop the fresh charge getting dragged out the exh.

I measured the LA 46 liner and got .039 for the side and .033 for the top flange which is thinner than the .25. The engine that I was working with had a.015 shim under the head. I keep reading that guys put an extra head shim to get a better stunt run. It would be good to know what the total shim height is that every one is using and make the liner flange bigger, say like .058 and only use one .005 shim under the head.Al

BrianI've marvelled at the LA46 for years. The LA46 numbers are terrible ... it shouldn't work as a good stunt motor....... but for some reason they work really well. The run is not a fullout two cycle..... its a really good stunt run as is,for almost everyone. I don't know why, I wouldn't have thought so but they work with the high timing and big blowdown. Go figure. I don't know if anyone has ever tried one with normal timing. Somehow I think an LA46 with normal timing wouldn't be an LA46.

Most people run them just as they come. There's A LOT more to getting a decent run than the supposedly "correct" timing numbers.

I measured the LA 46 liner and got .039 for the side and .033 for the top flange which is thinner than the .25. The engine that I was working with had a.015 shim under the head. I keep reading that guys put an extra head shim to get a better stunt run. It would be good to know what the total shim height is that every one is using and make the liner flange bigger, say like .058 and only use one .005 shim under the head.Al

I'm going to look at angling the ports a little towards non exh side of the cylinder. It won't be much help on fuel economy because the liner is so thin and any angle on the port sides won't have much effect. But every little bit counts in trying to stop the fresh charge getting dragged out the exh.

Brian, I have modified many LA46's over the years (something around 60) and discovered that the stock timing with the ports angled back 60 degrees away from the exhaust port did in fact significantly reduce fuel consumption on most of the engines. Also I'm convinced that it gives steadier runs in the mid range. Of course that's only an opinion based on running and flying many of them. There are of course other factors involved in fuel consumption but it does work on nearly every engine I reworked. There are still many of my engines floating around and they typically run very well. I never tried milder port timing but suspect it would do exactly as expected and as you say. I also experimented with a number of different head configurations but never found one that was enough of an improvement to justify the work.Given the quality of work you put into piston cylinder fit I'm sure these will be great runners.

Brian, I have modified many LA46's over the years (something around 60) and discovered that the stock timing with the ports angled back 60 degrees away from the exhaust port did in fact significantly reduce fuel consumption on most of the engines. Also I'm convinced that it gives steadier runs in the mid range. Of course that's only an opinion based on running and flying many of them. There are of course other factors involved in fuel consumption but it does work on nearly every engine I reworked. There are still many of my engines floating around and they typically run very well. I never tried milder port timing but suspect it would do exactly as expected and as you say. I also experimented with a number of different head configurations but never found one that was enough of an improvement to justify the work.Given the quality of work you put into piston cylinder fit I'm sure these will be great runners.

After a lot of consideration I'm prepared to proceed with these, but there is an increased cost/requirement.

We'll be ok with the thin wall of the liner but I want to increase the thickness of the top flange to ensure we can maintain a truly round bore and maintain the quality that everyone is acustomed to with our ABC sets.

This means that a new head will be mandatory adding a cost of approx $28-$30AUD per set.

Those that have requested to be put on the list for these can you please confirm you are still in.